Import VX multicall utility and applets

tests/test_xargs.sh

@@ -0,0 +1,35 @@
+#!/bin/sh
+# tests/test_xargs.sh - Tests for xargs applet
+_test_name="xargs"
+. "$(dirname "$0")/harness.sh"
+
+setup_tmpdir
+XARGS="$VX xargs"
+
+echo "Running xargs tests..."
+
+out="$(printf 'a\nb\n' | $XARGS echo ITEM:)"
+check_eq "$out" "ITEM: a b" "basic: appends stdin items"
+
+out="$(printf 'a\nb\nc\n' | $XARGS -n 2 echo CHUNK:)"
+check_eq "$out" "CHUNK: a b
+CHUNK: c" "nflag: max args"
+
+out="$(printf 'one\ntwo\n' | $XARGS -I '{}' echo X{}Y)"
+check_eq "$out" "XoneY
+XtwoY" "Iflag: replacement"
+
+out="$(printf 'one\ntwo\n' | $XARGS -J '{}' echo PRE POST '{}')"
+check_eq "$out" "PRE POST one two" "Jflag: replacement at custom position"
+
+printf 'aa\0bb cc\0' > nul
+out="$(cat nul | $XARGS -0 echo Z:)"
+check_eq "$out" "Z: aa bb cc" "0flag: NUL-delimited input"
+
+out="$(printf 'a\nb\n' | $XARGS -L 1 echo LINE:)"
+check_eq "$out" "LINE: a
+LINE: b" "Lflag: one line per command"
+
+check_exit "exit: bad option exits 1" 1 $XARGS --definitely-not-a-real-option
+
+summary